Analyte sensors and methods for making and using them

Abstract

Embodiments of the invention provide analyte sensors having elements designed to modulate their chemical reactions as well as methods for making and using such sensors. In certain embodiments of the invention, the sensor includes a hydrophilic comb-copolymer having a central chain and a plurality of side chains coupled to the central chain, wherein at least one side chain comprises a silicone moiety.

The invention claimed is: 
     
       1. An analyte sensor apparatus for implantation within a mammal, the analyte sensor apparatus comprising:
 a base layer; 
 a conductive layer disposed upon the base layer wherein the conductive layer includes a working electrode; 
 an analyte sensing layer disposed on the conductive layer, wherein the analyte sensing layer detectably alters the electrical current at the working electrode in the conductive layer in the presence of an analyte; and 
 an analyte modulating layer disposed on the analyte sensing layer, 
 wherein: 
 the analyte modulating layer modulates the diffusion of the analyte therethrough; 
 the analyte modulating layer comprising a hydrophilic comb-copolymer having a central chain and a plurality of side chains coupled to the central chain; 
 the hydrophilic comb-copolymer comprises a polydimethyl siloxane monomethacrylate, methyl methacrylate; and methoxy poly(ethylene oxide)monomethacrylate comb-copolymer; 
 the analyte modulating layer exhibits a glucose diffusion coefficient of between 2.3×10 −9  cm 2 /s and 140×10 −9  cm 2 /s; and 
 the analyte modulating layer comprises: 
 30-50 wt % polydimethyl siloxane monomethacrylate; 
 30-55 wt % methyl methacrylate; and 
 15-25 wt % methoxy poly(ethylene oxide)monomethacrylate, 
 such that the comb-copolymer exhibits a molecular weight from 139 kg/mol to 196 kg/mol. 
 
     
     
       2. The analyte sensor apparatus of  claim 1 , wherein analyte modulating layer exhibits a water uptake between 20% and 40%. 
     
     
       3. The analyte sensor apparatus of  claim 2 , wherein the analyte modulating layer has a oxygen diffusion coefficient (D oxygen ) to glucose diffusion coefficient (D glucose ) ratio (D oxygen /D glucose ) of from 5 to 2000. 
     
     
       4. An analyte sensor apparatus for implantation within a mammal, the analyte sensor apparatus comprising:
 a base layer; 
 a conductive layer disposed upon the base layer wherein the conductive layer includes a working electrode; 
 an analyte sensing layer disposed on the conductive layer, 
 wherein the analyte sensing layer detectably alters the electrical current at the working electrode in the conductive layer in the presence of an analyte; and 
 an analyte modulating layer disposed on the analyte sensing layer, 
 wherein: 
 the analyte modulating layer modulates the diffusion of the analyte therethrough; the analyte modulating layer comprising a hydrophilic comb-copolymer having a central chain and a plurality of side chains coupled to the central chain; and 
 the analyte modulating layer exhibits: 
 (a) a glucose diffusion coefficient of between 2.3×10 −9  cm 2 /s and 140×10 −9  cm 2 /s; 
 (b) a oxygen diffusion coefficient (D oxygen ) to glucose diffusion coefficient (D glucose ) ratio (D oxygen /D glucose ) of from 5 to 2000; and a water uptake between 20% and 40%; and 
 (c) the analyte modulating layer comprises: 
 30-50 wt % polydimethyl siloxane monomethacrylate; 
 30-55 wt % methyl methacrylate; and 
 15-25 wt % methoxy poly(ethylene oxide)monomethacrylate, 
 such that the comb-copolymer exhibits a molecular weight from 139 kg/mol to 196 kg/mol. 
 
     
     
       5. The analyte sensor apparatus of  claim 4 , wherein at least one side chain is hydrophilic. 
     
     
       6. The analyte sensor apparatus of  claim 4 , wherein at least one side chain is hydrophobic. 
     
     
       7. The analyte sensor apparatus of  claim 4 , wherein the central chain is hydrophilic.